In recent years, computer systems execute large-scale data processing such as online real-time processing, big data processing, and deep learning processing. The computer systems necessarily use a huge-capacity main memory device when such processing is performed. However, in the past, information processing devices such as servers include a dynamic-random access memory (DRAM) having high standby power as a main memory device. For this reason, in the computer systems according to the related art, power consumption is high when the large-scale data processing is executed.
Further, in recent years, computer systems in which a plurality of servers are connected via a network such as Ethernet or InfiniBand to perform a distributed process have been known. In such computer systems, processing can be performed at a higher speed than when a server executes processing alone. However, in such computer systems, a large amount of data is transferred between the servers. For this reason, in the computer systems in which the distributed process is performed, when the large-scale data processing is executed, a processing speed is decreased.